'Object does not have geometry data' error when running headless?
Quoting from https://docs.blender.org/api/242PythonDoc/API_related-module.html :
Background mode examples:
# Open Blender in background mode with file 'myfile.blend'
# and run the script 'script.py':

blender -b myfile.blend -P script.py

# Note: a .blend file is always required.  'script.py' can be a file
# in the file system or a Blender Text stored in 'myfile.blend'.

I have tested it but you can try adding a file in your command line options